the culprit- 2003 Tahoe LT 4x4 ~145k on the clock.
well maintained, all work done by professional mechanics on time.

I was driving home from a dinner the other night, leaving the driveway at about 15 mph I could tell something wasn't quite right. My idle increased, then suddenly acted like the engine was gasping for air, and then resumed normal drive. When I looked down, the truck had shifted from 2wd to 4L. Luckily, I wasn't going very fast. I tried returning to 2wd, and it wouldnt budge. Turned off the engine, fired it back up, put it in neutral and back into 2wd and then the "Service 4WD Soon" message came up. I parked it and haven't drive it since.


The previous night I had used 4L to tow another car out of a ditch, but had no problems. I had also used 4H after that when I was going to recover another truck in a wet field.

Also, days before I had a subwoofer professionally installed to the factory bose unit because I was told that the truck used DATALink and if I tried to do it I could potentially screw things up horribly...think this might have something to do with it?

Any help greatly appreciated.

Albert

 

The sub probly has nothing to do with it. it is more than likly the encoder motor (shifter motor) on the transfer case going out or possible the switch on the dash.

 

Welcome to the forum.

Try getting the codes scanned to see if it sheds any lite.